diff --git a/CHANGES.rst b/CHANGES.rst
index 61ffd97..a3990b3 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -3,12 +3,19 @@ Changelog
 
 For changes before version 3.0, see ``HISTORY.rst``.
 
-4.2 (unreleased)
+4.3 (unreleased)
 ----------------
 
 - Nothing changed yet.
 
 
+4.2 (2019-11-22)
+----------------
+
+- add a check if object is present ```if not db``
+  (`#91 <https://github.com/zopefoundation/AccessControl/issues/91>`_).
+
+
 4.1 (2019-09-02)
 ----------------
 
diff --git a/src/AccessControl/owner.py b/src/AccessControl/owner.py
index ea18fe6..e3d33bc 100644
--- a/src/AccessControl/owner.py
+++ b/src/AccessControl/owner.py
@@ -264,6 +264,8 @@ def ownerInfo(user, getattr=getattr):
     if uid is None:
         return uid
     db = aq_parent(aq_inner(user))
+    if not db:
+        return None
     path = [absattr(db.id)]
     root = db.getPhysicalRoot()
     while 1: